CTLA-4 promoter polymorphisms are associated with latent autoimmune diabetes in adults

The cytotoxic T lymphocyte antigen-4 (CTLA-4) molecule is an important regulator of T-cell activation and a susceptibility candidate for autoimmune diseases. To evaluate the impact of CTLA-4 promoter allelic variants of the CTLA-4 gene in latent autoimmune diabetes in adults (LADA), the MH30 (rs231806), -1147 (rs16840252), and -318 (rs5742909) single nucleotide polymorphisms (SNPs) were studied in a population of Estonian origin, including 61 LADA patients and 230 controls. The MH30 GG genotype (p = 0.0051) and the G allele (p = 0.0023) were significantly associated with LADA. The frequency distribution of alleles and genotypes of rs16840252 and rs5742909 SNPs were not significantly different between the patient and control groups. The frequency of the CTLA-4 GCC (p = 0.000073) haplotype was significantly higher in LADA patients, whereas the frequency of the CTLA-4 CCC (p = 0.0019) was significantly lower in LADA patients in comparison with the control group. The current study confirms the involvement of CTLA-4 gene promoter polymorphisms in the susceptibility of LADA and extends our previous findings of associations with other CTLA-4 polymorphisms.     

CTLA-4 gene polymorphisms and natural soluble CTLA-4 protein in psoriasis vulgaris

CTLA-4 molecule is an important inhibitor of T-lymphocyte activation. Several single nucleotide polymorphisms (SNPs) in the CTLA-4 gene were found, and their associations with many human diseases were described. So far, however, such studies have not been performed in psoriasis vulgaris in Caucasoids. Therefore, we examined the distribution of three CTLA-4 SNPs: -1147C/T, -318C/T and +49 A/G in 116 patients with psoriasis vulgaris and 123 healthy blood donors using the polymerase chain reaction-restriction fragment length polymorphism method. For all three SNPs, the frequencies of alleles, genotypes and three-point haplotypes were very similar in patients and controls, suggesting no contribution of these genetic variants to psoriasis.     

Association of CTLA-4 gene promoter polymorphisms with systemic sclerosis in Iranian population

In a recent study, we were unable to show any association between CTLA-4 exon-1 polymorphism and systemic sclerosis (SSc) in Iranian population. In order to further explore the role of this immune inhibitory gene in SSc development, in the present study, the polymorphisms in the CTLA-4 promoter region (-1,722 T/C, -1,661 A/G and -318 C/T) were investigated in 83 SSc patients and 166 healthy controls. All genotypes and allele frequencies in patients were significantly different from the control group (P=0.022 for -1,722 T/C, P=0.03 for -1,661 A/G and P=0.014 for -318 C/T genotypes). The -1,722C, -1,661G and -318T alleles contributed to SSc with P=0.012, odds ratio (OR) 2.16, P=0.031, OR 1.82 and P=0.023, OR 2.45, respectively. A significant difference was observed in the frequency homozygous 'genotype combination' -1,722TT/-1,661AA/-318CC of these three polymorphisms (P(c)=0.003). The frequency of this genotype combination was significantly higher in the control group than in patients. Results of this investigation indicate that -1,722C, -1,661G and -318T alleles of CTLA-4 gene promoter appear to be associated with SSc, and individuals carrying these alleles may be more susceptible to this disease.     

Distribution of CTLA-4 polymorphisms in allergic asthma

BACKGROUND: The CTLA-4 molecule is an important negative regulator of T cell activation. It is encoded on chromosome 2q33 and found to be associated with several allergic phenotypes including asthma. However, the association of CTLA-4 gene polymorphisms with allergic asthma is still controversial and therefore was the subject of this study. METHODS: By PCR-RFLP, the distribution of three single nucleotide polymorphisms (SNPs), -1147 C/T, -318 C/T, and +49 A/G, was examined in 219 Polish Caucasoid patients diagnosed with allergic asthma and in 102 ethnically matched healthy control individuals. (AT)(n) microsatellite polymorphism was also tested in the same individuals. RESULTS: No statistically significant differences in SNPs or microsatellite allele, genotype or haplotype frequencies between patients and controls were found. CONCLUSION: CTLA-4 polymorphisms do not seem to be a risk factor for allergic asthma in Poles.     

Impact of population admixture on the distribution of immune response co-stimulatory genes polymorphisms in a Brazilian population

Co-stimulatory molecules are essential in the orchestration of immune response and polymorphisms in their genes are associated with various diseases. However, in the case of variable allele frequencies among continental populations, this variation can lead to biases in genetic studies conducted in admixed populations such as those from Brazil. The aim of this study was to evaluate the influence of genomic ancestry on distributions of co-stimulatory genes polymorphisms in an admixed Brazilian population. A total of 273 individuals from the north of Brazil participated in this study. Nine single nucleotide polymorphisms in 7 genes (CD28, CTLA4, ICOS, CD86, CD40, CD40L and BLYS) were determined by polymerase chain reaction-restriction fragment length polymorphism. We also investigated 48 insertion/deletion ancestry markers to characterize individual African, European and Amerindian ancestry proportions in the samples. The analysis showed that the main contribution was European (43.9%) but also a significant contribution of African (31.6%) and Amerindian (24.5%) ancestry. ICOS, CD40L and CD86 polymorphisms were associated with genomic ancestry. However there were no significant differences in the proportions of ancestry for the other SNPs and haplotypes studied. Our findings reinforce the need to apply AIMs in genetic association studies involving these polymorphisms in the Brazilian population.     

Association studies of CTLA-4, CD28, and ICOS gene polymorphisms with B-cell chronic lymphocytic leukemia in the Polish population

Abnormal expression of the costimulatory molecules cytotoxic T-lymphocyte antigen 4 (CTLA-4), CD28, and inducible co-stimulator (ICOS) leads to disturbances of immune response and an increased risk of cancer. An extended study was undertaken to evaluate the association among the polymorphisms CTLA-4c.49A>G, CTLA-4g.319C>T, CTLA-4g.*642AT(8_33), CD28c.17+3T>C, and ICOSc.1554+4GT(8_15) and susceptibility to B-cell chronic lymphocytic leukemia (B-CLL) in the Polish population. The study revealed increased frequency of the CTLA-4g.319C>T [T] allele and the CTLA-4g.319C>T [T] phenotype in B-CLL patients compared with healthy controls (p = 0.003, odds ratio [OR] = 1.73; and p = 0.009, OR = 1.74, respectively). The presence of the CD28c.17+3T>C [C] allele and the CD28c.17+3T>C [C] phenotype increased the OR of B-CLL to 1.59 (p = 0.007) and 1.74 (p = 0.007), respectively. Either CTLA-4g.319C>T or CD28c.17+3T>C was associated with time to Rai stage progression. The distributions of the alleles and genotypes of the ICOS gene significantly differed between patients and controls (p = 0.0009 and p = 0.006, respectively). Individuals possessing short alleles were 2.02 times more prone to B-CLL than others (p = 0.001), whereas carriers of long alleles were protected from B-CLL (p = 0.02, OR = 0.62). The haplotype association study and multivariate analysis confirmed the association of CTLA-4g.319C>T and ICOSc.1554+4GT(8_15) gene polymorphisms with B-CLL. The polymorphic sites CTLA-4c.49A>G and CTLA-4g.*642AT(8_33) did not correlate with B-CLL. Our results are the first in the literature to report that gene polymorphism of the costimulatory molecules CTLA-4, CD28, and ICOS contributes to susceptibility to B-CLL.     

CTLA-4基因多态性与特发性扩张型心肌病的相关性

目的包括细胞和体液免疫在内的自身免疫机制至少参与了部分特发性扩张型心肌病(Idiopathicdilatedcar-diomyopathy,IDC)患者的发病,且前者介导的心肌损害在IDC中更重要。CTLA-4是特异性细胞免疫的负性调节因子。本研究旨在探讨CTLA-4基因启动子-318C/T、外显子A/G多态性及3′非翻译区(AT)n微卫星多态性与IDC及血清可溶性CT-LA-4(sCTLA-4)水平的相关性。方法采用聚合酶链反应-限制性片段长度多态性(Polymerasechainreaction-restrictionfragmentlengthpolymorphisms,PCR-RFLP)方法分析黑龙江省无血缘关系汉族人群(包括72例IDC患者,100例正常健康人)CTLA-4基因-318C/T、49位点A/G多态性及3′微卫星多态性;ELISA法检测血清sCTLA-4水平。综合分析CTLA-4基因型频率、等位基因频率与IDC及sCTLA-4水平的相关性。结果IDC组外显子1GG基因型和G等位基因频率显著高于正常对照组(P=0.012,P=0.008);3′非翻译区共发现18种等位基因,106bp等位基因频率在IDC患者中显著增高(22.22%vs1%,P=0.0002,OR=23.56,95%CI9.65~83.74);两组间-318C/T多态性分布无统计学差异。与对照组相比,IDC组sCTLA-4水平显著升高[(1.87±1.06)μg/L比(0.54±0.19)μg/L,P<0.05];直线回归分析显示,IDC组GG基因型及G等位基因频率与血清sCTLA-4水平(r=0.57,P=0.021)显著相关,而AA、A/G基因型及A等位基因频率与sCTLA-4水平无相关性。启动子-318C/T多态性及3′非翻译区(AT)n微卫星多态性与sCTLA-4水平的亦无相关性。结论CTLA-4基因外显子1A49→G变异与IDC相关,携带G等位基因者易患IDC,其机制可能为该多态性造成CTLA-4信号肽中编码苏氨酸和甘氨酸的替换,从而影响蛋白翻译后加工、修饰,使sCTLA-4功能发生变化。提示3′末端非翻译区(AT)n重复序列中106bp等位基因可能是IDC的易感基因。     

Lack of association between CD28/CTLA-4 gene polymorphisms and atopic asthma in the Japanese population

Atopic asthma occurs in genetically susceptible individuals in the presence of environmental factors. Recently, the costimulation signal from CD80-CD86 to CD28/CTLA-4 has been suggested to play an important role in the development of atopic asthma. In the present study, we analyzed three polymorphic regions within the CTLA-4 gene, an A/G substitution in exon 1 position 49, a C/T base exchange in the promoter position -318 and an (AT)n repeat polymorphism in the 3'-untranslated region of exon 4, and a CD28 gene polymorphism with a T/C substitution in intron 3 position +17 in 120 patients with atopic asthma and 200 normal controls. The polymorphism frequencies of CTLA-4/CD28 genes in patients did not differ from those in normal controls. Thus, the present study was unable to reveal any association between CTLA-4/CD28 gene polymorphisms and atopic asthma in the Japanese population.     

Correlation of CTLA-4 polymorphism and the risk of gastric cancer in a Chinese Bai population

Cytotoxic T lymphocyte-associated antigen-4 (CTLA-4) is involved in the regulation of immune responses mediated by T cells. This study aimed to explore the correlation between CTLA-4 gene polymorphisms and the risk of gastric cancer (GC) in the Bai minority population of southwestern China. A total of 422 GC patients and 397 healthy controls (HC) were included in this case–control study. Four single nucleotide polymorphism sites of CTLA-4 gene (rs231775, rs733618, rs16840252 and rs3087243) were selected and analysed. The results showed a significant difference in the rs733618 loci between GC and HC groups. The frequency of the rs733618 polymorphism ‘TC’ genotype was significantly lower in GC group compared to the HC group [odds ratio (OR), 95% confidence interval (CI): .47 (.35–.63), p < .001]. GC cases with dominant genetic model ‘TC + CC’ had a 47% reduced risk of GC [OR, 95%CI: .53 (.40–.71), p < .001]. Subgroup analyses revealed that the rs733618 ‘TC + CC’ genotype was associated with a lower risk of GC in male patients [OR, 95%CI: .42 (.31–.58), p < .001], those aged ≤60 years old [OR, 95%CI: .27 (.18–.42), p < .001], non-drinkers [OR, 95%CI: .21 (.13–.33), p < .001], non-smokers [OR, 95%CI: .38 (.25–.57), p < .001] and individuals without Helicobacter pylori infection [OR, 95%CI: .16 (.10–.26), p < .001]. Further multivariated analyses indicated that individuals with the ‘TC + CC’ rs733618 genotype who were aged ≤60 years old [OR, 95%CI: .42 (.29–.83), p = .032] and had no H. pylori infection [OR, 95%CI: .35 (.28–.76), p = .018] were found to have a protective effect against GC. Additionally, soluble CTLA-4 were significantly lower in GC patients with ‘TC’ and ‘TC + CC’ genotypes (all p < .05). Our findings suggest that the rs733618 polymorphism of CTLA-4 gene may play a critical role in the prevention of GC.     

No association of type 1 diabetes with a microsatellite marker for CTLA-4 in a Japanese population.

Susceptibility to insulin-dependent (type 1) diabetes mellitus is determined by both environmental and genetic factors. The primary gene associated with predisposition to type 1 diabetes is the human leukocyte antigen (HLA) class II gene (IDDM1). Recent studies have described linkage and association of type 1 diabetes to the cytotoxic T lymphocyte antigen-4 (CTLA-4) gene (IDDM12)in Caucasians. CTLA-4 is a candidate gene for T-cell-mediated autoimmune diseases because it is a negative regulator of T-cell proliferation. We investigated distribution of a CTLA-4 (AT)n microsatellite marker in 118 Japanese patients with type 1 diabetes and 195 control subjects. We also investigated association between this CTLA-4 gene polymorphism and GAD65 antibody positivity in 103 of the patients. CTLA-4 microsatellite marker loci were determined by polymerase chain reaction amplification of genomic DNA and resolution of the products on sequencing gels. GAD65 antibody was detected by radioligand binding assay. There was no significant difference in the distribution of CTLA-4 alleles between patients and controls, and no difference was observed in the prevalence of CTLA-4 alleles when GAD65 antibody-positive and -negative individuals with the type 1 diabetes were compared. The present study did not support an association between the CTLA-4 microsatellite marker and type 1 diabetes in our Japanese study population.     

Association between type 1 diabetes and polymorphism of the CTLA-4 gene in a Tunisian population]

Susceptibility to type 1 diabetes mellitus is strongly associated with particular HLA class II alleles. However, non HLA genetic factors are likely to be required for the development of disease. The candidate genes include the cytotoxic T lymphocyte associated 4 (CTLA-4) located on chromosome 2q33 and designated (IDDM12), which encodes a cell surface negative signal T molecule providing for activation. We investigated CTLA-4 exon 1 dimorphism in 74 type 1 patients and a control group of 48 healthy subjects from Tunisia using two methods PCR (polymerase chain reaction) allele specific and polymerase chain reaction restriction fragment length polymorphism (PCR RFLP). The CTLA-4/G allele was found on 68.9% in type 1 patients as compared to 51.02% in controls (p = 0.002), mostly in homozygous from 43.24% versus 22.45% (p = 0.0058). This results indicate that CTLA-4/G allele was significantly associated with predisposition to type 1 diabetes in our group from Tunisian population.     

Four tumor necrosis factor alpha genes polymorphisms and periodontitis risk in a Chinese population

Background

Tumour necrosis factor-alpha (TNF-alpha) has been implicated in the pathogenesis of generalized aggressive periodontitis (AgP) and chronic periodontitis (CP). The objective of the present study was to evaluate the association of four TNF-alpha gene polymorphisms (−1031T/C, −857C/T, −308G/A and −238G/A) with susceptibility to AgP and CP in a Chinese population.

Methods

A hospital-based case-control study was conducted in in patients with CP (n = 180), AgP (n = 180) and healthy controls (n = 180). Gene promoter polymorphisms were analyzed by polymerase chain reaction–restriction fragment length polymorphism (PCR–RFLP) assay. Genotype and allele frequencies were analyzed using the chi-square test and logistic regression analysis.

Results

TNF-alpha −1031CC genotype was significantly higher [odds ratio (OR) = 2.36, 95% confidence interval (CI) = 1.03, 5.43; P = 0.04] in patients with CP compared with healthy controls. TNF-alpha −308AA genotype was significantly higher (OR = 2.71, 95% CI = 1.09, 6.73; P = 0.03) in patients with AgP compared with healthy controls. No association was found of TNF-alpha −857C/T and −238G/A polymorphisms with susceptibility to AgP or CP.

Conclusions

Our data demonstrated that TNF-alpha −1031CC genotype was a risk factor for CP, and that TNF-alpha −308AA genotype was a risk factor for AgP. But there is a lack of association of TNF-alpha −857C/T and −238G/A polymorphisms with susceptibility to AgP or CP in a Chinese population.     

High-resolution HLA typing for the DRB3/4/5 genes by sequence-based typing

The high degree of polymorphism of the HLA genes at the nucleotide sequence level has proven sequence-based typing a major typing strategy. For DRB1 the allelic variability is predominantly present in the second exon and by DNA sequencing of exon 2 all hitherto known DRB1 alleles can be detected. For the associated genes DRB3, DRB4 and DRB5 the situation is slightly different. Allelic differences are not limited to exon 2 and the sequence of exon 3 and sometimes exon 4 is needed for complete subtyping. Oligonucleotides to amplify the exons needed for subtyping of DRB3, DRB4 and DRB5 were designed. Gene-specific products were generated to make simultaneous detection of alleles in heterozygous combinations possible. In this way 238 individuals were fully typed for their DRB3, 4 and 5 subtypes. Additional samples were typed for only one of the genes. All samples had been previously typed by PCR-SSP. Concordant typing results were obtained for all individuals tested. The DRB3 alleles typed for included *0101, *0201, *0202 and *0301, for DRB4 they were *01011, *0102 and *0103 and for DRB5 *0101, *0102, *0103, *0105, *0201, *0202 and *0203. All alleles were easily detected by the protocol described except for DRB5*0201. Sequencing of exon 3 and 4 of the DRB5*0201 allele showed this allele to be a sequencing error and the sequences obtained were identical to the exon 2, 3 and 4 sequences of DRB5*0202. Two new alleles were identified in the samples studied, DRB4*0105 and DRB3*0207. Sequence based typing has been recognized as a valuable tool for HLA typing of DRB1, DQB1 and DPB1 since several years. It is shown to be a superior typing method as well in the detection of the different DRB3, 4 and 5 subtypes.     

4p14区段和CTLA-4基因多态性与Graves病相关

目的探讨中国安徽蚌埠地区汉族人群4p14区段位点rs6832151和CTLA-4基因4个SNPs(单核苷酸多态性)位点基因多态性与Graves病相关性,和基因-基因交互作用对Graves病的影响。方法提取611例诊断明确的GD患者和644名健康对照者的全基因组DNA,用Taq Man探针技术进行基因分型,使用Plink和Haploview等统计软件分析这些位点与蚌埠地区汉族人群Graves病的相关性。结果 4p14区段位点rs6832151的等位基因、基因型频率在GD组和对照组之间有差异(P0.05),CTLA-4基因区域内rs231804和rs231726两个SNP位点基因型在显性模型下差异显著(P0.05);GMDR模型显示CTLA-4基因内rs10197319、rs231726、rs231804、rs1024161位点和4p14区段内rs6832151位点组成的五阶模型(P=0.001)为最佳模型,CTLA-4基因内rs1024161和rs10197319位点之间上位效应分析结果有差异(P0.05)结论 4p14区段rs6832151,CTLA-4基因区域内rs231804和rs231726位点基因多态性与蚌埠地区汉族人群Graves病的遗传易感性相关;rs6832151(4p14区段)和rs10197319、rs231726、rs231804、rs1024161(CTLA-4基因)5个SNP位点间的基因-基因交互作用与Graves病相关,CTLA-4基因内rs1024161和rs10197319位点之间存在上位效应。     

HLA-G alleles and HLA-G 14 bp polymorphisms in a Brazilian population

Brazilians represent one of the most heterogeneous populations in the world as the result of five centuries of interethnic crosses. We investigated the polymorphism of the HLA-G locus in a Brazilian urban sample. HLA-G alleles were determined by SBT analysis of exons 2-4 and 8 in 103 unrelated individuals. The genotyping analysis identified 11 different HLA-G alleles, including the recently described G*010110 allele, and four new variants in this population. These data indicate that this Brazilian population presents high HLA-G allelic polymorphism, suggesting increased levels of intrapopulational genetic diversity that may be because of the admixed nature of the sample. This is the first study regarding HLA-G genotyping that was performed at such refined resolution level in this heterogeneous population.     

Epitopes recognized by CBV4 responding T cells: effect of type 1 diabetes and associated HLA-DR-DQ haplotypes

The present study aimed at characterizing the epitopes recognized by coxsackievirus B4 (CBV4)-specific T-cell lines established from 23 children with type 1 diabetes (T1D) and 29 healthy children with T1D risk-associated HLA genotypes. Responsiveness to VP1 region was dependent on the specific infection history as 55% of the T-cell lines from donors with neutralizing antibodies to CBV serotypes responded to VP1 peptides compared to none of the T-cell lines from other donors (P = 0.01). The pattern of recognized peptides was dependent of the HLA genotype. Forty-two percent of the T-cell lines from donors carrying the HLA-(DR4)-DQB1*0302 haplotype responded to VP1 peptides 71-80 compared to none of the T-cell lines from donors without this haplotype (P = 0.02). No evidence for the existence of diabetes-specific epitopes was found. Only few epitopes were exclusive recognized by T cells from diabetic children, and in each case only one or two T-cell lines were responding.     

Evaluation of genetic damage in a Brazilian population occupationally exposed to pesticides and its correlation with polymorphisms in metabolizing genes

Cytogenetic damage in individuals occupationally exposed to pesticides has received the attention of investigators in several countries, but no definitive conclusions can yet be made. The present study aimed at assessing if prolonged exposure to complex mixtures of pesticides leads to an increase in cytogenetic damage. Vineyard workers exposed to pesticides in Caxias do Sul (Brazil) were evaluated using the micronucleus (MN) test in binucleated lymphocytes and the comet assay in peripheral leukocytes. In order to evaluate if genetically determined individual variations in xenobiotic metabolizing capacity could modify individual susceptibility to the possible genotoxic effects of pesticides, the subjects were genotyped for several genes: GSTT1, GSTM1, GSTP1, CYP1A1, CYP2E1 and PON. The study involved a total number of 173 men: 108 were agricultural workers exposed to pesticides and 65 were controls. The present study showed a high rate of MN and DNA damage in pesticide-exposed individuals (P 相似文献